In the field of metal packaging, “easy open” ends for metal cans are well known. Typically, an easy open can end includes a pull tab and an approximately planar panel having a score line defining an opening area. To open a can having an easy open can end, a user may lift a handle of the pull tab to initiate fracture of the score line, and a user may subsequently pull the tab to partially or fully remove a portion of the panel, thereby creating an opening through which a user may access the contents.
Typically, the gap between the pull tab handle and the can end panel is very small. This small gap may make it difficult for a user to grasp the pull tab, because there may not be enough clearance under the pull tab for a user to insert a finger. Therefore, typical easy open cans may be difficult for a user to open.
A can end that has a moveable portion disposed beneath a handle of its tab has been developed by Crown Cork & Seal. This can end—known commercially as the Easylift™ can end—is disclosed in U.S. application Ser. No. 11/613,909, the contents of which are incorporated by reference in their entirety. The Easylift™ can end has a moveable portion that is deformable from an upward position to a downward position. In the upward position, the can end is readily stackable for transportation (i.e. before being attached to a container body), but provides little or no clearance between the can end and the tab. When deformed into the downward position (typically after being attached to a can body), the deformed moveable portion then provides clearance between the tab and can end to enable a user to engage their fingers with the tab and open the can.
While the moveable portion may be deformed into a downward position using a mechanical force, ideally the downward position is achieved utilizing a pressure differential across the can end. For example, before the can end is attached to the can body, the can body is filled with a hot comestible product. After the can end is attached, the hot product cools down gradually and approaches ambient temperature. This lower temperature, as well as resulting steam that is trapped inside the container, may result in a low-pressure period. This reduced pressure inside the container may produce a downward force (i.e. vacuum) acting on the moveable portion to thereby deform the moveable portion into a downward position without the use of a mechanical panel pusher.
Because it is ideal to deform the moveable portion into a downward position utilizing a pressure differential across the can end, there is a need for improved can ends and methods for manufacturing can ends having such capabilities.